If the image formed by a mirror for all positions of the object placed in front of it is always erect and diminished, what type of mirror is it? Draw a ray diagram to justify your answer. Where and why do we generally use this type of mirror?

The mirror is a convex mirror as convex mirror always forms an image which is virtual, erect and diminished, when the object is placed in front of the mirror.

The Ray diagram is as follows:

Convex mirrors are used in following applications:

1. In vehicles: Convex mirrors are used as rear-view mirrors in vehicles because the image obtained with the help of convex mirror is highly diminished in size and thus gives a wider field of view and helps the driver of the vehicle to view the traffic in much larger area behind the vehicle.

2. In shops: Convex mirrors are installed in shops to avoid the stealing of items by any customer or thieves. The shopkeeper can keep an eye on customer as a convex mirror forms a virtual, erect and diminished image and thus acts as shop security mirror.